Compressor unit



1934- J. w. CUTHBERT 1,969,999

COMPRES SOR UNIT Filed March so, 1951 Y 2 Sheets-Sheet 1 Q ATTORNEYS.

Aug. 14, 1934.

' J. w. CUTHBERT COMPRESSOR UNIT Filed March 30. 1931 2 Sheets-Sheet 2 Hg 5K A TTORNE YS.

Patent ed Au 14,1934

UNITED v STATES- PATENT OFFICE.

2 Claims.

This invention is for a compressor unit, and has special reference to a compressor of the eccentric displacement type.

The main object of the invention is to provide a compressor unit of high efiiciency which will compress gases to high pressure in a single stage, and which will, by its method of operation remove the heat of compressionfrom the gases during the compression period.

Another object of the invention is to provide a compressor unit in which oil is fed under pros sure to the inside of the piston, and through the piston in restrictedamount for the purpose of sealing the piston and cooling the gas during the period of compression, by supplying oil to the gas contacting surfaces of the compressor and ejecting the surface oil with the compressed gas into a receiver, where the oil is separated fromthe gas and circulated through a cooling device, from whence it is delivered to the compressor. A further object of the invention is to provide the unit with means for cooling the oil previous to introduction into the compressor, and providing means in the oil circuit for automatically discontinuing the circulation of oil when the pressure in the receiver drops below a predetermined pressure, and automatically restoring the circulation when the pressure is increased.

A further object of the invention is to provide a compressor unit which is self-cooling, self-sealing and self-lubricating and which is automatically controlled by the operation thereof.

My 1 copending application, Serial Number 526,338, filed March 30, 1931, is directed to the oiling and gas cooling system for this unit.

Other objects and advantages of the invention will become apparent as the following description is read on the drawings forming a part of this specification, and in which similar reference characters are usedto indicate similar parts throughout the several views, and in which:

Fig. l'is a front elevation of the compressor unit;

Fig.-'2 is. a side sectional elevation of the invention;

Fig.- 3 is an end view of the compressor with end plate or cover removed;

Fig. 4 is a transverse section through the compressor showing the intake and exhaust ports and exhaust valve in detail;

Fig. 5 is an elevation in half section of the oil separator;

Fig. 6 is a longitudinal sectional elevation -through the compressor per se; Fig. 7 is a section taken on line '77 of Fig. 4;

Fig. 8 is a sectional elevation through the pressure actuated oil valve; and

Fig. 9 is a diagrammatic view showing the piston at'point of intermediate travel.

The invention consists of a compressor forming part of, and'housed within a receiver, oil storage and cooling means, oil circulating means, oil. control means, oil separating means and an automatic unloader for the receiver, forming an integral self-controlling gas cooling unit of high efflciency.

The cover coincidently forms a cover for the receiver and an end plate for the compressor, and consists of a plateportion 10, a flange 11 and a bearing boss 12, the boss and plate portion being provided with a plurality of radial ribs or fins 13, the flange being provided with a plurality of bolt "holes 14. Bolt holes are also provided about the "hub 12 to receive bolts 15 of the compressor. The

plate is pipe tapped from both sides at 16 to receive the oil circulating pipes.

The hub 12 has a ball bearing 17 mounted therein for cooperation with the shaft 18, and is also provided with a pocket 19 which is packed with suitable packing 20 and retained by a packing nut 21 in which the shaft 18 is rotatable. A concentric boss 22 cooperates with a counterbore 23 on the compressor.

The receiver consists of a housing 24 which is substantially elliptical in cross-section, and which is provided with a plurality of cooling fins 25. Tapped holes are provided for cooperation with the bolts 26 by which the cover 10 is bolted to the receiver flange 27. Feet 28 are cast integral with the housing and are provided with suitable anchor bolt holes 29. A pipe tap 30 adjacent the bottom of the interior of the receiver provided for draining the oil, and also for reception of the oil circulating pipe 31. Bores are provided for the exhaust L 32 and intake pipe 33 which are suitably packed to retain the high pressures within the. receiver.

The compressor may consist of one or more sections or stages and as shown in the drawings is for a tandem compressor, each section of which consists of a cylinder 34 having a bore 35 extending therethrough and a counterbore 23 formed at each end for cooperation with bosses or annular shoulders 22 formed on the cooperating center and end plates. Through bolt holes 36 receive bolts 15 by which the compressor is bolted together. Intake passages consist of a bore 3'7 extending longitudinally throughout the cylinder wall, a slot 38 formed in the inner wall and communicating with the bore 3'7 throughout is L10 length, and a port 39 communicating with the bore 37 and extending through the manifold seat 40. The exhaust consists'of a small aperture 41 opening into the interior of the cylinder, a counterbore 42 terminating in a seat for the valve, which consists of a disc 43 which is limited as to movement by an adjustable member 44 and seated over the aperture 41, the adjustable member 44 being secured in a plate 45 which is bolted to the cylinder as at 46, and is provided with exhaust holes 47. A bore 48 extends throughout the length of the cylinder wall and has a slot 49 extending throughout the length thereof, the bore 48 receiving the pivot 50 of the dividing plate 51 which forms a dividing Wall between the intake 38 and exhaust 41, the slot 49 being properly formed to permit reciprocal movement of the plate 51, which extends throughout the length of the cylinder. The most efiicient location of slot 49 has been determined, and is substantially equal to 17 percent of the radius from the periphery of the piston.

The space between the insideof the cylinder wall and the valve seat or the valve 43, is made a minimum to decrease the compression space within the bore 41. The upper wall of slot 49 intersects the periphery of the bore 41, and the dividing plate 51 substantially cooperates with the top wall of the slot when the piston is in its final exhaust position, only suflicient clearance being provided, as is customary, to prevent knocking. By this means the maximum restriction ofthe final compression space is provided and maximum exhaust of compressed gases. obtained, while coincidentally the intake space is increased, thereby increasing the overall efficiency of the compressor.

The piston consists of a sleeve 52 having a central bore 53 in which is secured ball bearings 54 spaced apart by a sleeve 55 which has an oil hole 56 through which oil is fed from the eccentric shaft to the bore 53. A restricted oil hole 57 in the piston is adapted to feed just sufficient oil to provide a seal between piston and cylinder in addition to the amount necessary to absorb the heat of compression of the gas during compression. The size of the oil hole is' obtained by trial, and when once found, remains constant for a specific type of oil and displacement.

The compressor sections are spaced apart and isolated from each other by means of the center plates 58 which are provided with annular shoulders as indicated at 22 cooperating with the counterbores 23, and have each a counterbore in which a radial ball bearing 59 is securely mounted and by the outer race of which the two plates are aligned.

The end plate 60 is also provided with an annular shoulder 22 and has a counterbore in which a ball bearing 61 is mounted, A pipe tap 62 communicates with the end of shaft 18 and ball bearing 61.

The intake manifold is provided with ports 63 which communicate with ports 39 in the cylinders, and have a communicating passage 64 with a common intake 33, which extends out of the receiver and the end of which is equipped with an air filter or cleaner 55.

The oil separator consists of a cover member 66 whiclris provided with a threaded aperture 67 in the hub thereof. The body 68 is removably secured to the cover by means of through bolts 69, and a plurality of openings 79 are formed through the walls. The separator frame consists of walls 73, ribs 74 and a baifie 75 and is retained between the cover and body, and rests on} of a tubular element having a gravity actuated valve .81 which permits the oil to flow out but prevents the compressed gas from passing through the bottom.

The separator is secured in place by means of' the outlet L 32, the threaded end of which cooperates with the threaded aperture 6'7. v v

The Outlet L 32 has a side tap or outlet 82,-to which is connected an unloader 83 which.may consist of any satisfactory type, and preferably a solenoid actuated valve which is in circuit with the motor switch, and connected to the L 32 by means of a pipe 84. The usual check valve, not shown, is connected in the pipe line 85 between the L 32 and storage device. The oiling system consists of the oil supply 86 in the receiver 24, which is conducted by means of the pipe 31 to a radiator or cooling coil 87 to a pressure actuated valve 88, and thencethrough the pipe 89 to end plate tap 62,through the central bore 99 and bleeder holes 91 in the 1 crankshaft and through holes .56 in sleeves 55 and holes 57 in pistons 52, exhaust valve 41.

thence out through the The pressure actuated valve 88 consists of a.

body 92 having an upper valve chamber 93-and' bersnormally closed by a ball valve 96. The

lower chamber 94 has a side outlet 97 into which the oil pipe 89 is'threadedly secured. A sylphon 98 is secured in the sylphon chamber by means 100 communicating with the interior of the sylphon and which is connected by means of a pipe 101 to the pipe 84 adjacent to the unloader 83. The sylphon 98 has an integral seat 192 on which rests a plunger 103 which is slidable in the bearing 104. A spring 105 urges the sylphon to normal retracted position. The cap 106 is threadedly secured at the top of the valve chamber and has a central tap 107 into whioh'is threadedly secured a pipe 108 in communication with the cooling coil 87. The valve described is a necessary feature in the efiicient operation of the corn pressor unit, and is the subject of a separate application filed Mar. 30, 1931, Serial No. 526,340.

'of the removable base 99 which has a central t'ap The operation of the compressor unit is as 1301- H thrown in circuit, the unloader is instantiy closed,

thereby sealing the receiver against escape of air except through the outlet 85.

As the shaft 18 is rotated, the'eccentrics 109 move the pistons 52 about an orbital path conforming to the eccentricity, the piston being pre vented from rotating by the dividing plate 51 which forms a wall between the intake-and ex- The piston does not touch the cylhaust points. I inder walls during its orbital travel, but has a slight clearance obviating any wear on the inside I of the cylinder or periphery of the piston.

A slight oscillating motion is produced within sure is thus built up by the 0 follows the wall closely, the gas is'forced ahead and compressed, finally being completely driven out through the exhaust due to the small volume of bore 41 and the location and disposition of the plate 51. Referring to Fig. 9, free gas is being drawn in the chamber formed at 110 which increases in size, while the previous charge is being compressed in the chamber formed at 111, finally being driven out through the valve 41'. A presgas ejected from the valve 41 into the receiver, which pressure is transmitted through the 32, pipes 84, and 101, to the inside of the sylphon 98, expanding the sylphon,

raising the plunger103 which raises the ball 96 ofi itsseat. The gas pressure in the receiver 24 acts on the oil supply 86 and forces the oil out through pipe 31, through cooling coil 87 into the top of the valve housing at 107, past ball '96- through passage 95 and out through 9'7, pipe 89- to the end plate ,at 62, thence through the central bore 90 in shaft 18, out through the holes 91, maintaining the space between ball bearings 54 substantially full of oil. As the piston 52 moves about, the oil is forced through the bleeder holes 57 into the intake chamber, which is regulated by the speed, which decreases the pressure in 110, higher speed delivering more oil, and higher pressure in the receiver also increasing the amount of oil.

' i oil is forced about with the air during the compression period providing a seal between the piston and cylinder, absorbs the heat of com- .pression from the gas and is mostly ejected withthe compressedgas through exhaust valve 41,- into the receiver 24. The gas mixed with oil must pass through the separator, Fig. 5, where the oil iscollected by the filter material 78 and drained'out through the outlet 80. The compressed gas with the oil first passes through openings 70 thence down underneath the screen 77 upward through the screen and filter medium 78 and out through the L 32 and conduit 84.

This compressor unit runs cool under long continued periods of operation and showed exceptionally high efiiciency, as also the abilityto compress to very high pressures in a single stage.

scope of the invention or sacrificing any of the advantages thereof.

I claim:

1. A compressor unit comprising a casing, means dividing said casing into two axially aligned cylinders, the wall of each cylinder having a longitudinally disposed gas-inlet bore provided with a longitudinal slot throughout its length and establishing communication between the cylinder and the bore, each cylinder having an exhaust port independent of the exhaust port of the other cylinder, a common gas-inlet for said gas-inlet bores, a separator blade pivotally mounted in the wall of each cylinder at a position between the gas-inlet bore and the exhaust port, eccentrics located within the respective cylinders, and pistons mounted on the respective eccentric, each piston having a chordal slot therein complemental to said separator blade.

2. A compressor unit comprising a casing having a cylinder therein, the wall of said cylinder having a longitudinally disposed gas-inlet bore inder at a position between said bore and the' exhaust port, an eccentric 'rotatably mounted within the cylinder, said eccentric consisting of two eccentric members separated by an intermediate cylindrical sleeve, a shaft on which said eccentric is mounted, and a piston on the eccentric, said piston having a chordal slot therein complemental to the separator blade.

- JOSEPH. w. CUTHBERT. 

